Co-creator, with her husband Gerry, of such futuristic puppet series as
Thunderbirds and Stingray

Sylvia Anderson, who has died aged 88, co-created the television puppet series Thunderbirds with her husband Gerry Anderson; she was also the inspiration for – and voice of – Lady Penelope, the husky-toned aristocrat turned secret agent.

The couple had met in the 1950s through their work with Polytechnic Films, a small production company based in Buckinghamshire. At the time, Sylvia Thamm was employed as a secretary; Gerry, meanwhile, was already married with two daughters. In 1956 Anderson broke away to found AP Films, taking Sylvia with him. They married in 1960 and Sylvia’s role broadened to put her on an equal footing with her husband.

Sylvia Anderson and Lady Penelope in London, 1995

Gerry Anderson had never intended to work with puppets, and said as much in the course of his career. It took a visit from Roberta Leigh, a wealthy children’s author and animator, to persuade the couple that a marionette show might be commercially viable. “Because we were desperate we agreed to do it,” Sylvia Anderson recalled. The result was Torchy the Battery Boy (1960), a faintly sinister creation with a fixed stare and an X-ray lamp mounted in his forehead. For their subsequent projects involving puppetry, Gerry developed a technique that he dubbed Supermarionation. Using thin wires in the puppets’ heads, the lip and eye movements could be electronically synched to correspond with pre-recorded dialogue.

While Gerry Anderson honed the technology, Sylvia focused on plot and character development. On the back of their early success with half-hour shows such as Stingray (1964), she persuaded the television impresario Lew Grade to grant them an hour-long broadcast slot. The result was Thunderbirds, which followed the life-saving exploits of the Tracy family – a father and his five sons – from their futuristic island base in the Pacific. Assisting them was Brains, a bespectacled genius with a stammer, and Lady Penelope Creighton-Ward, the Tracys’ eyes and ears in London.

Lady Penelope with her butler and chaffeur Parker

It was the latter character that truly fired the imaginations of the public and the press. With her immaculate fashion sense and Sylvia Anderson’s equally immaculate vowels, Lady Penelope introduced a degree of sophistication specifically intended to attract an American audience. “[The Americans] didn’t like puppets, really,” Sylvia Anderson recalled, “but I knew they would quite like the idea of a lady, an English lady, living in a stately home.” Critics hailed Lady Penelope as a “pop-feminist” who, like her television contemporary Emma Peel in The Avengers, combined glamour with intelligence. More than six million viewers tuned in for the series’ original run.

With this, their first great commercial success, Gerry and Sylvia Anderson were free to expand their horizons. Two feature-length Thunderbirds films followed. Sylvia Anderson also wrote for Captain Scarlet (1967), and worked with Gerry as co-creator and costume designer on three subsequent productions: Joe 90 (1968), The Secret Service (1969), and UFO (1970). Meanwhile, the Andersons’ merchandise empire – including toys, books and games – turned over more than £3 million during the 1960s. The couple attended the London premiere of Thunderbirds Are Go (1966) in a life-size replica of Lady Penelope’s pink Rolls-Royce.

Lady Penelope in her pink Rolls-Royce

Behind the scenes, however, life was rather less glamorous. Sylvia Anderson looked back on their most successful creative period as a time of frequent arguments and trial separations. After the marriage finally ended in 1975, a bitter dispute arose around the significance of her professional role, which came to focus on the origins of Lady Penelope. Sylvia Anderson recalled that a puppet maker for the show had based the character’s facial features on her, only revealing the decision after the series came to an end. Gerry, for his part, claimed that the character was entirely his own, and that the look came from a model in a shampoo advertisement. Tensions between the pair were exacerbated by a protracted custody battle over their son, Gerry Jr, during which communication broke down completely. “As far as I’m concerned”, the older Gerry once declared, “She no longer exists.” The two were never reconciled, and Gerry Anderson died of Alzheimer’s in 2012.

Sylvia Thomas was born in London on March 27 1927, the daughter of Sidney Thomas, a boxing promoter, and Beatrice, a dressmaker. After attending the London School of Economics – where she was president of the dramatic society – she worked as a social worker in England and America. Following the collapse of her first marriage, to an American professional golfer, she settled in London and took a part-time job at Polytechnic Films.

"A lot of men have told me that Lady Penelope was their first crush."

In the years after her separation from Gerry, she joined HBO as a London-based talent scout and made occasional forays into acting. Unlike her ex-husband, she expressed delight at the casting of Sophia Myles as Penelope in a live-action 2004 film. When Thunderbirds was revived as a television series in 2015, Sylvia Anderson had a vocal cameo as Lady Penelope’s great-aunt. Certain elements of her fan-base baffled her, however. “A lot of men have told me that Lady Penelope was their first crush. I can’t understand that.”

Sylvia Anderson’s autobiography, My Fab Years, was published in 2007.

In addition to her marriage to Anderson, she had a brief first marriage, to Jack Brooks, which ended in divorce. In 1952, she married, secondly, George Thamm. That marriage was also dissolved. She is survived by a son and daughter.